HSG Test: What to Expect, Does It Hurt, and What Your Results Mean
If you are having a fertility evaluation, you may be told that you need an HSG test. Then you search for it, read a few painful stories, and start wondering what you have signed up for.
An HSG, or hysterosalpingogram, is an X-ray procedure that evaluates the inside of the uterus and determines whether the fallopian tubes appear open. It is an important fertility test because a regular vaginal ultrasound cannot give us all of this information.
The pain experience is different for everyone. Most patients describe pressure or an intense menstrual cramp as the dye enters the uterus and travels through the tubes. For many, the most intense part is brief. Certain medical histories, a blocked fallopian tube, or the technique used during the procedure may make an HSG more painful.
Knowing what will happen and what questions to ask beforehand can help you walk into the appointment better prepared.
HSG Test Explained: Pain, Timing, and Understanding Your Results
Timestamps:
00:00 What Is an HSG Test?
00:36 What an Ultrasound Cannot Show
01:57 Why Fertility Doctors Order an HSG
02:33 When Should an HSG Be Scheduled?
03:18 What Happens During the Procedure?
03:33 Does an HSG Hurt?
03:51 Why an HSG May Be More Painful
04:09 Questions to Ask About Pain Control
05:00 Who May Have a Higher Risk of Pain?
05:21 Understanding Your HSG Results
05:39 What Does a Filling Defect Mean?
06:09 Saline Sonogram vs. Hysteroscopy
06:36 Can You Get Pregnant With One Open Tube?
07:06 What Do Blocked Fallopian Tubes Mean?
07:45 Could a Blocked Tube Be a Spasm?
08:18 What Is a Hydrosalpinx?
09:27 Why Hydrosalpinx Matters Before IVF
09:57 Is the Fear Worse Than the HSG?
What is an HSG test?
HSG stands for hysterosalpingogram. During the test, contrast dye is placed through the cervix and into the uterus. X-ray images show the shape of the uterine cavity and track whether the dye travels through the fallopian tubes and spills out of their ends.
If the dye moves through a tube and spills into the pelvis, that tube appears open. If the dye stops, the tube may be blocked or temporarily spasming.
An HSG can help identify:
An abnormal shape inside the uterus
Possible uterine birth differences
Filling defects that may represent a polyp, fibroid, scar tissue, blood clot, or thickened lining
A partially or fully blocked fallopian tube
A blocked and dilated tube called a hydrosalpinx
The HSG does not show the ovaries, diagnose endometriosis, or identify every type of fibroid. It is one part of a fertility evaluation, not a complete evaluation by itself.
Why can’t a vaginal ultrasound show whether my tubes are open?
This surprises many people.
The uterus is a potential space. When it is resting, the front and back walls of the uterine cavity sit against each other. A vaginal ultrasound can evaluate the uterine muscle, endometrial lining, and ovaries, but it may not clearly show what is sitting inside the collapsed cavity.
The fallopian tubes are also usually too small to see on a standard ultrasound unless they are enlarged or filled with fluid.
Think about the uterine cavity like an empty AirPods case that is closed. From the outside, you can evaluate the shape of the case, but you cannot see exactly what is inside it. Once fluid separates the walls, an abnormality can interrupt the space where the fluid should go. On an HSG, this may appear as a filling defect.
The contrast dye also travels through the fallopian tubes. That is the part of the test that helps us determine whether the tubes appear open.
When should an HSG be scheduled?
An HSG is usually performed after menstrual bleeding has ended but before ovulation. In many fertility clinics, that means approximately cycle days 6 through 10, with cycle day 1 being the first day of full menstrual flow.
This timing matters for two reasons.
First, the uterine lining is still relatively thin. A thick lining can make the cavity harder to evaluate or mask an abnormality.
Second, performing the test before ovulation reduces the possibility of exposing an early pregnancy to the procedure.
The timing may be different if you take birth control pills because the medication keeps the lining thin and prevents ovulation. Follow the scheduling instructions from your own clinic, since cycle length and medical history may change the recommended window.
What happens during an HSG?
The beginning of an HSG feels similar to a Pap test.
You lie on an exam table, and a speculum is placed in the vagina so the cervix can be seen. The cervix is cleaned, and a small catheter or cannula is passed through the cervical opening. Contrast dye is slowly injected into the uterine cavity while X-ray images are taken.
As the uterus fills, its walls separate slightly. The dye should then move into the fallopian tubes and spill out of their ends if they are open.
The procedure itself is usually short. The American Society for Reproductive Medicine describes an HSG as an outpatient procedure that generally takes less than five minutes to perform, although the full appointment will take longer.
Does an HSG hurt?
Most people feel cramping when the dye enters the uterus. It may feel like pressure, fullness, or an intense menstrual cramp.
For many patients, the strongest cramp lasts less than a minute. Mild or moderate cramping may continue after the procedure. Some people experience more significant pain, and that experience should not be minimized.
One reason an HSG can hurt more is a blocked fallopian tube. If fluid is pushed toward a blockage, it can back up and stretch the uterine cavity or tube.
The way the cervix is handled may also affect the experience. Some clinicians use an instrument called a tenaculum to hold the cervix steady. This is not always necessary, but it is worth asking whether one will be used and what pain-control options are available.
ACOG recommends discussing pain relief when the procedure is first planned, rather than waiting until the day of the test.
Who may be more likely to experience pain?
Talk with your care team before the procedure if you have a medical history that raises concern for tubal disease, pelvic adhesions, or a more difficult procedure.
That may include:
A prior ectopic or tubal pregnancy
Previous fallopian tube surgery
Known or suspected endometriosis
Previous abdominal, pelvic, or bowel surgery
A ruptured appendix
A history that makes tubal damage or blockage more likely
These factors do not guarantee that the procedure will be painful. They are reasons to have a more detailed conversation about what to expect and what pain-control options the facility can provide.
What should I ask before my HSG?
Call the clinic before the appointment so you are not trying to make decisions while lying on the procedure table.
Useful questions include:
What do you recommend taking before the procedure for pain?
Will you use a tenaculum to hold the cervix?
If a tenaculum is needed, is local numbing medication available?
Does the clinic offer other medication for pain or anxiety when appropriate?
Should I arrange for someone to drive me home?
Will I need antibiotics based on my medical history?
When and how will I receive my results?
Options vary among clinics. ACOG notes that pain relief may include an over-the-counter medication taken before the procedure or local anesthetic applied to the cervix. Some facilities may have additional options. Ask what is medically appropriate for you and what is available where your test will be performed.
What do HSG results mean?
Your HSG report should describe the uterine cavity, whether dye moved through each fallopian tube, and whether the dye spilled freely into the pelvis.
The next step depends on what the images show.
A filling defect inside the uterus
A filling defect means the dye did not completely fill part of the uterine cavity.
This does not tell us exactly what is there. The finding could represent a polyp, fibroid, scar tissue, blood clot, or an area obscured by the uterine lining.
Your care team may recommend a saline sonogram to evaluate the cavity more closely. A saline sonogram uses fluid and ultrasound to separate the uterine walls. It can provide more detail about a possible polyp or fibroid, but a standard saline sonogram does not provide the same information about whether the fallopian tubes are open.
Another option is hysteroscopy. During a hysteroscopy, a small camera is passed through the cervix into the uterus. Hysteroscopy is considered the gold standard for evaluating the uterine cavity because it allows the clinician to see inside the uterus directly. It may also allow a polyp, fibroid, or scar tissue to be treated during the same procedure.
One open fallopian tube
Pregnancy may still be possible with one healthy, open fallopian tube.
Fallopian tubes have some mobility within the pelvis. An open tube may sometimes capture an egg released from the opposite ovary. Your overall chance of pregnancy still depends on age, ovulation, semen parameters, the condition of the remaining tube, and other fertility factors.
One open tube does not automatically mean that IVF is required. Your care team will interpret the finding within your complete fertility evaluation.
A proximal tubal blockage
A proximal blockage is located near the point where the fallopian tube meets the uterus.
This result may represent a true obstruction, but it can also occur when the tubal opening temporarily spasms during the test. The speed or pressure used to inject the dye may contribute to spasm.
For this reason, a proximal blockage on HSG does not always settle the question. Your physician may recommend repeating the test or evaluating the tube another way before making a treatment decision. ASRM recognizes false-positive proximal blockage as one limitation of HSG.
A distal tubal blockage
A distal blockage occurs at the far end of the fallopian tube, closer to the ovary.
This type of blockage is more likely to reflect tubal damage related to previous inflammation, infection, endometriosis, bleeding, surgery, or pelvic adhesions. The amount of damage and whether the tube is dilated will influence the next recommendation.
A hydrosalpinx
A hydrosalpinx is a fallopian tube that is blocked at its far end and dilated with fluid.
The tube normally produces secretions that move out through its open end. When the end is blocked, fluid can collect inside the tube and sometimes flow back toward the uterine cavity.
Hydrosalpinx matters because it may reduce the chance of pregnancy, including with IVF. If an HSG suggests a hydrosalpinx, your fertility specialist may recommend removing the affected tube or separating it from the uterus before an embryo transfer. The recommendation will depend on the full clinical picture.
Most people with a hydrosalpinx do not notice a specific symptom. Some may have pelvic discomfort or unusual watery vaginal discharge, but these symptoms are not enough to diagnose the condition.
What should I expect after an HSG?
Mild cramping, light spotting, or a small amount of sticky discharge can occur after the procedure as the contrast fluid leaves the uterus.
Some patients are prescribed antibiotics based on their history or the findings of the test. Antibiotics are not handled identically by every clinic. If they are prescribed, take them exactly as directed.
ACOG advises contacting your clinician for symptoms such as:
Severe abdominal pain or cramping
Heavy vaginal bleeding
Fever or chills
Foul-smelling vaginal discharge
Vomiting or fainting
Your own clinic may give you additional instructions about intercourse, exercise, medications, or follow-up.
Can an HSG show a false blockage?
Yes, especially when the apparent blockage is proximal, near the uterus.
A fallopian tube may temporarily spasm as the dye is injected. If the dye does not pass through, the resulting image can look like a blockage even when the tube is not permanently closed.
This is why the location of the blockage matters. Your physician may need another study or procedure before deciding whether the tube is truly obstructed.
Can you get pregnant with one blocked fallopian tube?
Pregnancy may be possible when one tube is blocked and the other is healthy and open.
The answer also depends on age, ovarian reserve, ovulation, semen analysis, the cause and location of the blockage, and whether there are other fertility concerns. An HSG result should be interpreted as one part of the full picture.
Is an HSG necessary before IVF?
An HSG may still provide valuable information even when IVF is planned.
IVF bypasses the fallopian tubes for fertilization, but a blocked and dilated tube can affect the environment inside the uterus. Identifying a hydrosalpinx before an embryo transfer may change the treatment plan and improve the chance of success.
Uterine cavity evaluation is also an important part of preparing for an embryo transfer. Your physician will determine which test is most appropriate based on your history and prior imaging.
The fear can be worse than the procedure, but preparation still matters
I order HSG tests as part of many fertility evaluations. The majority of my patients tell me that their fear beforehand was worse than the procedure itself.
That does not mean every experience is easy. Pain varies, and your medical history matters. You should be able to ask how the procedure will be performed, what pain-control options are available, and what the possible results could mean before the test begins.
Understanding your uterus and fallopian tubes gives you information that a regular ultrasound cannot provide. Know what the test is looking for, ask your questions ahead of time, and make sure there is a plan for reviewing the results.
Medical review and sources
This article is based on educational guidance from Dr. Natalie Crawford and current patient and professional resources from:
American College of Obstetricians and Gynecologists: Hysterosalpingography
American Society for Reproductive Medicine: Hysterosalpingogram
ASRM Committee Opinion: Role of Tubal Surgery in the Era of Assisted Reproductive Technology
Natalie Crawford, MD, is a doctor, but she is not your doctor. This content is for general education and is not a substitute for individualized medical care.